1. Field of the Invention
The present invention relates to optical communication equipment and, more specifically but not exclusively, to line cards.
2. Description of the Related Art
This section introduces aspects that may help facilitate a better understanding of the invention(s). Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art.
An optical line card is used for interfacing optical communication lines, e.g., carrying optical signals to and from the subscribers, to the rest of the telecommunications access network. A typical optical line card is a modular opto-electronic circuit assembled on a printed circuit board. Its representative modules may include an optical transmitter, an optical receiver, an optical add/drop multiplexer, a digital signal processor, a controller, a power-management unit, a performance monitor, various optical and electrical interfaces, etc.
Different modules of an optical line card may be implemented using monolithic integration. A monolithic integrated circuit is usually fabricated on a single piece of semiconductor substrate, e.g., by (i) incorporating dopants into the substrate, (ii) depositing and patterning additional layers of material, and (iii) metallizing and packaging the resulting chip.